NIST has developed a novel pulse quantizer using arrays of Josephson junctions to create a pulse voltage output that is immune to differential pulse timing shifts. This invention will improve the accuracy and signal purity of synthesized waveforms by eliminating timing shifts that degrade performance.
The superconducting waveform synthesizer consists of an input w[n] that is a three-level delta-sigma encoding of a target output waveform. The bitstream is then used by a pattern generator to synthesize a series of three-level current pulses. These pulses are transferred to a cryogenic superconducting JAWS chip containing an array of Josephson junctions, which transforms the input current pulses to output voltage pulses with quantized area.
This bipolar realization with two arrays is a more practical and useful implementation because it will increase the output voltage and eliminate DC offsets from the output signals. The resulting output waveform will be free from pulse timing shifts, improving the accuracy and signal purity of the synthesized waveform.
Source: https://www.nist.gov/patents/deformometer-determining-deformation-optical-cavity-optic
Keywords: Quantum Standards, Josephson Junctions, Superconducting Waveform Synthesizer, Arbitrary Waveform, Pulse Quantizer
